The present invention relates to an electrophotographic image forming apparatus, a developing device which is detachably mountable to a main assembly thereof and a process cartridge which is detachably mountable to the main assembly.
Here, the electrophotographic image forming apparatus is an apparatus forming an image on a recording material using an electrophotographic image formation process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a laser beam printer, LED printer or the like), a facsimile machine and a word processor.
The process cartridge may be a cartridge which contains as a unit an electrophotographic photosensitive drum and charging means, developing means or cleaning means and which is detachably mountable to the main assembly of the image forming apparatus. The process cartridge may be a cartridge which contains as a unit an electrophotographic photosensitive drum and at least one of charging means, developing means and cleaning means and which is detachably mountable to the main assembly of the image forming apparatus. The process cartridge may be a cartridge which contains as a unit an electrophotographic photosensitive drum and developing means and which is detachably mountable to the main assembly of the image forming apparatus.
In an image forming apparatus using an electrophotographic image process, such a process cartridge is used. This is because the maintenance of the apparatus can be carried out in effect by the user without the serviceman, so that operativity is remarkably improved. Therefore, the process cartridge type is widely used in the field of the image forming apparatus.
Also widely used is a developing device in the form of a cartridge which contains as a unit developing means and a toner container accommodating toner to be supplied into the developing means and to which is detachably mountable to the main assembly of an image forming apparatus.
Where the developer used in the developing device or the process cartridge is two component developer, there is provided detecting means for detecting a mixing ratio of the toner and the carrier. The developing means is supplied with a DC voltage and an AC voltage.
The developing device or the process cartridge is supplied from the main assembly with a driving force for driving the photosensitive drum and the developing means therein.
The present invention provides a further development of such technique.
It is a principal object of the present invention to provide a process cartridge, a developing device and an electrophotographic image forming apparatus wherein the mounting-and-demounting operativity of the process cartridge relative to the main assembly of the apparatus is improved.
It is another object of the present intention to provide a process cartridge, a developing device and an electrophotographic image forming apparatus wherein a connector part is substantially free of electrical influence.
It is a further object of the present invention to provide a process cartridge, a developing device and an electrophotographic image forming apparatus wherein the mounting-and-demounting operativity of the process cartridge relative to the main assembly of the apparatus is improved and wherein a connector part between the main assembly of the apparatus, and a detecting member for detecting a mixing ratio of the toner and the carrier is not influenced by a high AC voltage applied to a developing member, so that operation is stabilized. It is a further object of the present invention to provide a process cartridge and a developing device wherein a connector part, a developing member drive receiving portion and a developing bias contact are arranged efficiently, and an electrophotographic image forming apparatus to which the process cartridge or the developing device is detachably mountable. According to an aspect of the presentation, there is provided a process cartridge, a developing device and an electrophotographic image forming apparatus to which the process cartridge or the developing device is detachably mountable, wherein the connector part and the developing bias contact are disposed with a developing member driving force receiving portion therebetween.
According to another aspect of the present invention, there is provided an electrophotographic image forming apparatus wherein said connector portion, said developing member driving force receiving portion and said developing bias contact are arranged such that they are positioned in this order from a top side to a bottom side of the process cartridge, when said process cartridge is mounted to the main assembly of the apparatus.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.